I don't see what's overwhelming. They've put out Yet Another web system with some odd constraints. Unless you want to use another database over the web, your app will be locked into a proprietary database system that you can't run (or even test with) anywhere else.

For GAE to change the game, I would think they'd have to make it a lot easier for people to create web apps (not "here's some of django and some other CGI you can use").

GQL is especially weird, since it's a limited SQL-ish thing that no one else supports or necessarily will support. I'm a fan of the new SPARQL language for querying RDF, partly because SPARQL is the kind of standard system that google *could* map to their database. RDF predicates (aka google datastore 'keys' aka SQL 'columns') are more precise than any of the other systems, so it's never lossy to adapt an existing DB system to RDF.

Doesn't facebook have an FBQL that's also an arbitrarily reduced version of SQL? Maybe it's not for the same purpose at all, but just the presence of these things is training everyone to accept a new, proprietary query language for every system we deal with :(